The rise of circulatory endothelin (ET)-1 and endothelin receptors (ETA, ETB) expression in kidney of obese wistar rat.

Background: Endothelin (ET)-1, a circulatory protein, and its receptors (ET_A and ET_B) in various organs were reported to play a pivotal role in many diseases, including obesity. However, the changes of ET_A and ET_B expression in ventricle and kidney in obesity was less reported. The study is designed to observe the level of circulatory ET-1 and expression of ET_A/ET_B in ventricle and kidney of obese, as compared to non-obese, Wistar rats.

Methods: Groups of obese 14 and 34 weeks Wistar rats were compared to non-obese controls at similar ages. The obesity status was achieved by feeding the with high calories protein diet CP 551 + milk powder, while the control group was fed with a standard calorie protein AD II diet. The concentration of circulatory ET-1, ET_A and ET_B of ventricle and kidney were measured by Enzyme Linked Immunosorbent Assay (ELISA) technique after the termination of both groups at 14^th and 24^th weeks.

Results: The level of circulatory ET-1, expression of ET_A and ET_B in kidney, and LDL of obese rats were significantly higher than control rats (T-Test, P<0.05) in the elder groups, while no differences of the ET_A and ET_B were found in the ventricle. No differences of the levels of circulatory ET-1, ET_A and ET_B expression were found between obese and control groups of younger rats (P>0.05). HDL levels were under normal value for both groups.

Conclusion: Obesity in elder obese rats leads to dysregulation of kidney vessels through activity of ET-1 and ET_A/ET_B.